KR20140074427A - Method of manufacturing nano structure and method of forming a pattern using it - Google Patents

Abstract

Provided is a method for manufacturing a nanostructure. The method for manufacturing a nanostructure according to an embodiment of the present invention comprises the steps of forming a first thin film comprising a first block copolymer on a substrate; forming guide patterns on the first thin film; forming a second thin film including a second block copolymer between the guide patterns; and curing the second thin film, wherein the first block copolymer has a cylindrical shape, and the second block copolymer has a lamellar shape.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of fabricating a nanostructure,

The present invention relates to a method for producing a nanostructure and a pattern forming method using the same.

An organism with a hierarchical structure has been found through self assembly which forms a structure by itself in the natural world. Relevant research has been drawing attention to reproduce the chemical production method of nanostructures formed from such organisms and apply them academically and commercially. Such self-assembling phenomenon is also found in block copolymers which are one of the polymers that can be synthesized chemically.

Block copolymers are a type of polymeric material, in which two or more polymers link the ends of each other through covalent bonds. A diblock copolymer, which is the simplest structure of a block copolymer, is formed by two polymers having different tendencies connected to each other to form a polymer. The two polymers connected to each other are easily phase-separated due to their different material properties, and finally the block copolymer can self-assemble to form a nanostructure.

It is important to form a thin film on a substrate and induce stable nanostructure formation in the nanostructure in order to widen the practical application range of the nanostructure produced using the block copolymer. However, the block copolymer in the thin film state has a problem that the nano structure is formed differently from the bulk phase due to the interaction between the self-assembled material and the substrate, or the nano structure is arranged in an undesired form. To solve this problem, techniques for controlling the orientation and alignment of nanostructures for thin film samples have been developed. In general, an electric field is used to adjust the orientation or alignment of the nanostructures, or an epitaxial self-assembly method or a graphoepitaxy method is used. However, with the technologies developed up to now, there is a limit to forming the nanostructure uniformly on the large-sized substrate.

SUMMARY OF THE INVENTION The present invention provides a method of fabricating a nanostructure having a high degree of alignment and a pattern forming method using the same.

A method of fabricating a nanostructure according to an embodiment of the present invention includes forming a first thin film including a first block copolymer on a substrate, forming a guide pattern on the first thin film, 2 block copolymer, and curing the second thin film, wherein the first block copolymer is a cylinder type and the second block copolymer is a lamella .

After the step of curing the second thin film, the second thin film may be converted into a sacrificial structure including a first sacrificial block and a second sacrificial block.

The guide pattern may be formed of a photoresist.

The first block copolymer may comprise a crosslinking material.

The crosslinking material may comprise one of ketene, azide or benzocyclobutene (BCB).

The second block copolymer may be selected from the group consisting of PS-b-PMMA (polystyrene-block-polymethylmethacrylate), PS-b-PEO (polystyrene-block-polyethyleneoxide), PS- PS-b-PDMS (polystyrene-block-polydimethylsiloxane), PS-b-PFS (polystyrene-block-polyferrocenyldimethylsilane) or PS-b-PI (polystyrene-block-polyisoprene).

The method may further include ultraviolet treatment or heat treatment of the first thin film.

And forming an intermediate layer between the substrate and the first thin film.

The first block copolymer of the cylinder type may form a hexagonal type monomer unit.

A method of forming a pattern according to an embodiment of the present invention includes forming a first thin film including a first block copolymer on a substrate on which a parent pattern layer is formed, forming a guide pattern on the first thin film, Forming a second thin film including a second block copolymer between the first sacrificial block and the second sacrificial block; curing the second thin film to form a sacrificial structure including a first sacrificial block and a second sacrificial block; 1 sacrificial block; and patterning the first thin film and the parent pattern layer using the second sacrificial block as a mask, wherein the first block copolymer is cylindrical, and the second block copolymer The coalescence is lamella.

The guide pattern may be formed of a photoresist.

The guide pattern may include a photoresist pattern portion extended along a first direction, and the photoresist pattern portion may be repeatedly arranged in a second direction different from the first direction.

The first block copolymer may comprise a crosslinking material.

The crosslinking material may comprise one of ketene, azide or benzocyclobutene (BCB).

The second block copolymer may be selected from the group consisting of PS-b-PMMA (polystyrene-block-polymethylmethacrylate), PS-b-PEO (polystyrene-block-polyethyleneoxide), PS- PS-b-PDMS (polystyrene-block-polydimethylsiloxane), PS-b-PFS (polystyrene-block-polyferrocenyldimethylsilane) or PS-b-PI (polystyrene-block-polyisoprene).

The method may further include ultraviolet treatment or heat treatment of the first thin film.

And forming an intermediate layer between the parent pattern layer and the first thin film.

The parent pattern layer may be patterned in a line lattice pattern.

The parent pattern layer may comprise a reflective metal.

The first block copolymer of the cylinder type may form a hexagonal type monomer unit.

As described above, according to one embodiment of the present invention, the alignment degree of the plate-shaped block copolymer can be increased by forming an unaligned cylindrical block copolymer before forming the plate-like block copolymer.

1 is a perspective view of a nanostructure according to an embodiment of the present invention.
FIGS. 2 to 6 are perspective views illustrating a method of fabricating a nanostructure according to an embodiment of the present invention.
7 and 8 are a perspective view and a sectional view for explaining a pattern forming method according to an embodiment of the present invention.
9 is a perspective view of a pattern formed using the nanostructure of FIG.
10 is a cross-sectional view taken along line XX in FIG.
11 is a photograph showing a sorting effect when a plate-shaped block copolymer is formed on a cylindrical block copolymer according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that the disclosure can be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

In the drawings, the thicknesses of layers and regions are exaggerated for clarity. Also, when a layer is referred to as being "on" another layer or substrate, it may be formed directly on another layer or substrate, or a third layer may be interposed therebetween. Like numbers refer to like elements throughout the specification.

Nano structure

1 is a perspective view of a nanostructure according to an embodiment of the present invention.

Referring to FIG. 1, a neutral layer 120 is positioned on a substrate 110. The neutral layer 120 can grow steadily with perpendicularity in a direction perpendicular to the surface of the substrate 110, with the cylinder blocks SB1 and SB2 formed thereon. Neutral layer 120 exhibits chemical neutrality that is neither hydrophilic nor hydrophobic.

The neutral layer 120 may include an organic monolayer 120 including a self-assembled monolayer (SAM), a polymer brush and a cross-linked random copolymer mat (MAT) or a cross-linked random copolymer mat (MAT) .

Specific examples of the material forming the self-assembled monolayer include pentyltrichlorosilane (PETCS), phenyltrichlorosilane (PTCS), benzyltrichlorosilane (BZTCS), and tolyltrichlorosilane (TTCS) 4-biphenylyltrimethoxysilane (BPTMS), 2 - [(trimethoxysilyl) ethyl] -2-pyridine Octadecyltrichlorosilane (OTS), 1-naphthyltrimehtoxysilane (NAPTMS), 1 - [(trimethoxysilyl) methyl] naphthalene (1 - [(trimethoxysilyl) methyl] naphthalene: MNATMS), (9-methylanthracenyl) trimethoxysilane (MANTMS), and the like.

Specific examples of the polymer brushes include polystyrene-random-poly (methylmethacrylate), PS-random-PMMA.

Specific examples of the MAT include benzocyclobutene-functionalized polystyrene-random-poly (methacrylate) copolymer (Benzocyclobutene-functionalized polystyrene-r-poly have.

Although not shown, the surface of the substrate 110 may be pretreated with an acidic solution before the neutral layer 120 is formed. By this pretreatment, the affinity between the substrate 110 and the neutral layer 120 can be improved. An example of the acidic solution is hydrofluoric acid (HF).

According to the present embodiment, the cylinder structure SS is formed on the neutral layer 120. The cylinder structure SS includes a first cylinder block SB1 and a second cylinder block SB2 formed on the neutral layer 120. [ In this embodiment, the cylinder structure SS comprises a crosslinking material. Here, the crosslinking material includes one of ketene, azide or benzocyclobutene (BCB).

In the present embodiment, the cylinder structure SS including the crosslinking material forms the first block copolymer and includes the first nanoblock NB1 and the second nanoblock NB2 on the cylinder structure SS And a plate-like structure NS is formed. The plate-shaped structure NS forms a first thin film on the cylinder structure SS.

The first nanoblock NB1 extends in a first direction D1 of the substrate 110 and is disposed apart from the first direction D1 in a second direction D2. The second direction D1 may be perpendicular to the first direction D1. The second nanoblocks NB2 extend in the first direction D1 and are spaced apart in the second direction D2. Each of the second nanoblocks NB2 is disposed between adjacent first nanoblocks NB1.

Specific examples of the material forming the first nano block NB1 include poly (methylmethacrylate), PMMA, poly (ethylene oxide), PEO, poly (vinylpyridine) poly (vinyl pyridine), PVP], poly (ethylene-art-propylene), poly (ethylene-alt-propylene), PEP and polyisoprene. A specific example of the material forming the second nano block NB2 includes polystyrene. The nanostructure NS can be formed using a block copolymer in which the polymer constituting the first nanoblock NB1 and the polystyrene constituting the second nanoblock NB2 are mixed at a composition ratio of about 50:50.

Manufacturing method of nanostructure

FIGS. 2 to 6 are perspective views illustrating a method of fabricating a nanostructure according to an embodiment of the present invention.

Referring to FIG. 2, a neutral layer 120 is formed on a substrate 110. The substrate 110 may comprise a glass substrate. The neutral layer 120 is a chemically neutral layer that does not have hydrophilic or hydrophobic properties as described above and is a self-assembled monolayer (SAM), a polymer brush, and a cross-linked random copolymer mat ) Or a cross-linked random copolymer mat (MAT) or the like.

Although not shown, the surface of the substrate 110 may be pretreated with an acidic solution such as hydrofluoric acid (HF) before the neutral layer 120 is formed.

Referring to FIG. 3, a cylinder structure SS is formed on a substrate 110 on which a neutral layer 120 is formed. The cylinder structure SS is formed by synthesizing a crosslinkable block copolymer. Here, the crosslinkable block copolymer includes one of ketene, azide or benzocyclobutene (BCB).

The crosslinkable block copolymer containing ketene may be a compound represented by the following general formula (1).

[Chemical Formula 1]

Where m can be approximately 50-500, k can be approximately 50-500, and n can be approximately 1-40.

For example, a block copolymer of the ketene series can be synthesized based on the following Reaction Scheme 1 and the following Reaction Scheme 2.

[Reaction Scheme 1]

[Reaction Scheme 2]

Copolymers can be synthesized via RAFT polymerization of monomers containing a RAFT agent, including MMA (metyl meth acrylate) and xanthate. Here, AIBN is 2,2'-Azobis (2-methylpropionitrile), m is 50-500, n is 50-500, and k is 1-40. When heat of about 200-300 degrees centigrade is applied, a plurality of keten react with each other to form a crosslinking.

The PMMA macro-initiator in Scheme 1 may have a number average molecular weight of approximately 1-100 kg / mol and a PDI (polydispersity index) of approximately 1.9.

In the scheme 2, the number average molecular weight of the block copolymer of the ketene series may be approximately 10-100 kg / mol, and the content of the ketene may be adjusted to 1-20 mol%. In this embodiment, the amount of ketene and polystyrene to be added and the volume fraction of PMMA to be added in the reaction formula 2 are adjusted to 7: 3 to form a cylindrical block copolymer.

In the reaction schemes 1 and 2, cross-linking occurs through heat treatment, so that the cylinder structure SS can be resistant to an organic solvent that can be used in a subsequent process. UV treatment may be used instead of heat treatment.

As shown in FIG. 3, the cylinder structure SS includes a first cylinder block SB1 and a second cylinder block SB2. The first cylinder block SB1 may include PMMA, and the second cylinder block SB2 may include PS. As shown, the second cylinder block SB2 may be a substrate that substantially surrounds the first cylinder block SB1. Here, the cylinder structure SS can form a hexagonal type unit A. And has a first interval (L1) in the hexagonal type unit (A).

Referring to FIG. 4, a guide pattern GP is formed on the cylinder structure SS. The guide pattern GP can be formed through a photolithography process using a photoresist. After forming a photoresist film on the cylinder structure SS, a guide pattern GP formed of a photoresist material can be formed by irradiating light on the top of the mask to develop the photoresist film. The guide pattern GP is not limited to the photolithography process but can be formed by other methods such as a nanoimprint process.

The guide pattern GP controls the directionality of the second block copolymer to be formed later. The distance between the gut patterns GP may be less than about 1 um. However, when the guide pattern (GP) is formed by a photolithography process, the thickness of the guide pattern (GP) may be formed to be 1.5 μm or more considering the resolution limit of the photo equipment.

Referring to FIG. 5, a second thin film 140 is formed by applying a second block copolymer between the guide patterns GP by spin coating or the like. The second block copolymer is a polymer in which two different kinds of monomers are covalently bonded. The two different monomers have different physical and chemical properties. Accordingly, any one of the first monomers has a relatively hydrophilic property relative to the other second monomer, and the second monomer has a relatively hydrophobic property as compared with the first monomer. The second block copolymer according to the present invention comprises polystyrene and a polymer covalently bonded to the polystyrene.

As a specific example of the first block copolymer, the second block copolymer 140 may include polystyrene-block-poly (methylmethacrylate), PS-b-PMMA, polystyrene- (Ethylene oxide), PS-b-PEO], polystyrene-block-poly (vinylpyridine), PS-b-PVP], polystyrene- (Ethylene-allyl-propylene), polystyrene-block-poly (ethylene-altpropylene), PS-b-PEP and polystyrene-block-polyisoprene have.

Referring to FIG. 6, the substrate 110 including the second thin film 140 is heat-treated. The heat treatment process may be performed at a temperature of about 200 degrees Celsius to about 300 degrees Celsius, N2 or vacuum conditions for about 2 hours or more. UV treatment may be used instead of heat treatment. After the heat treatment, the second thin film 140 is converted into the plate-like structure NS including the first nanoblock NB1 and the second nanoblock NB2. Hereinafter, the first nanoblock NB1, the second nanoblock NB2, and the plate-like structure NS will be described as the first sacrificial block, the second sacrificial block, and the sacrificial structure, respectively.

The sacrificial structure NS is aligned along the first direction D1 and is phase-separated into polystyrene and polymer along the second direction D2. Thus, a first sacrificial block NB1 extending along the first direction D1 is formed and phase-separated from the first sacrificial block NB1 to be arranged in the second direction D2 of the first sacrificial block NB1 The second sacrificial block NB2 is formed. In an embodiment of the present invention, the first victim block NB1 comprises PS and the second victim block NB2 comprises PMMA.

The second block copolymer has a different shape depending on the composition ratio of the first and second monomers. When the composition ratio of polystyrene and PMMA is about 50:50, the sacrificial structure (NS) has a lamella shape.

The second gap L2 indicating the distance between the first sacrificial block NB1 and the second sacrificial block NB2 in the present embodiment is the distance between the first gap L1 of the cylinder structure SS It is preferable to form them substantially the same. As described above, if the first spacing L1 is made close to the second spacing L2 to about 1: 1, the degree of alignment of the plate-like structure NS can be increased. Hereinafter, this will be described with reference to FIG.

Thus, according to the present embodiment, a nanostructure including a plate-like structure NS is formed on a substrate 110 on a cylinder structure SS.

Hereinafter, a method of forming a pattern using the above-described nanostructure will be described.

How to form a pattern

7 and 8 are a perspective view and a sectional view for explaining a pattern forming method according to an embodiment of the present invention. 8 is a cross-sectional view taken along line VIII-VIII in FIG.

7 and 8, the mother pattern layer 200, which is a target material to be patterned in the above-described method of fabricating a nano structure, is formed on the substrate 110 (FIG. 7) before forming the neutral layer 120 or the cylinder structure SS. The pattern pattern layer 200 is formed. Then, the same process is performed until the step of forming the plate-like structure NS.

Next, as shown in FIGS. 7 and 8, the second sacrificial block NB2 is removed from the sacrificial structure NS. Accordingly, the first sacrificial block NB1 and the guide pattern GP remain on the cylinder structure SS which is the first thin film.

The second sacrificial block NB2 may be removed by wet etching. For example, if the substrate 110 containing the sacrificial structure NS is immersed in a solution containing acetic acid and then sonicated, only the second sacrificial block NB2 is selectively removed from the sacrificial structure NS. Alternatively, the second sacrificial block NB2 may be removed by dry etching. For example, after the sacrificial structure NS is irradiated with ultraviolet light, only the second sacrificial block NB2 can be selectively removed by a difference in etching selectivity through reactive ion etching (RIE) .

The upper surface of the parent pattern layer 200 can then be removed by etching the cylinder structure SS and the neutral layer 120 using the first sacrificial block NB1 as a mask. At this time, the parent pattern layer 200 can be patterned by removing the parent pattern layer 200 on which the top face is exposed.

Then, the first sacrificial block NB1, the guide pattern GP and the cylinder structure SS are removed. For example, the substrate 110 containing the first sacrificial block NB1, the guide pattern GP, and the cylinder structure SS is immersed in a solution containing toluene or the like, and then ultrasonically decomposed to form a first sacrificial block NB1 ), The guide pattern GP and the cylinder structure SS can be removed.

9 is a perspective view of a pattern formed using the nanostructure of FIG. 10 is a cross-sectional view taken along line X-X in Fig.

The pattern shown in Figs. 9 and 10 may be a metal pattern constituting a polarizing plate. Referring to FIGS. 9 and 10, the mother pattern layer 200 is patterned using the above-described nanostructure, thereby forming a line 210 including a first line 210a and a second line 210b formed on the substrate 110, A grid pattern 210 is formed.

The first and second lines 210a and 210b extend in a first direction D1 of the substrate 110. The second line 210b is disposed in a second direction D2 different from the first direction D1 of the first line 210a. The first and second lines 210a and 210b may include aluminum, silver, platinum, and the like.

According to this embodiment, a cylinder structure SS including a first block copolymer is formed using a block copolymer, and a plate structure NS including a second block copolymer is formed to form a parent pattern layer 200 ) Are patterned to form a line grid pattern 210. Accordingly, it is possible to form a nano-sized line grid pattern 210 having a high degree of alignment on the large-area substrate 110, thereby improving the manufacturing reliability and productivity of the polarizer.

11 is a photograph showing a sorting effect when a plate-shaped block copolymer is formed on a cylindrical block copolymer according to an embodiment of the present invention.

11A is a photograph showing a pattern of alignment after forming a guide pattern and a block copolymer therebetween, and FIG. 11B is a photograph showing a guide pattern and a guide pattern on a block copolymer of a cylinder structure according to an embodiment of the present invention. And the alignment pattern after the heat treatment.

It can be seen that the alignment degree is higher in the alignment pattern photograph shown in FIG. 11B than the alignment pattern photograph shown in FIG. 11A. Also, referring to FIG. 11B _{,? C61} indicates the first interval described above, and _L denotes a second interval. As a result of the experiment, it can be seen that the closer the ratio of the first interval to the second interval is closer to 1: 1, the higher the degree of alignment.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Of the right.

110: substrate 120: neutral layer
140: second thin film SS: cylinder structure
NS: nanostructure

Claims (20)

Forming a first thin film comprising a first block copolymer on a substrate,
Forming a guide pattern on the first thin film,
Forming a second thin film including the second block copolymer between the guide patterns, and
And curing the second thin film,
Wherein the first block copolymer is a cylinder type and the second block copolymer is a lamella. The method of claim 1,
Wherein the second thin film is converted into a sacrificial structure including a first sacrificial block and a second sacrificial block after curing the second thin film. 3. The method of claim 2,
Wherein the guide pattern is formed of a photoresist. 4. The method of claim 3,
Wherein the first block copolymer comprises a crosslinking material. 5. The method of claim 4,
Wherein the cross-linking material comprises one of ketene, azide or benzocyclobutene (BCB). 5. The method of claim 4,
The second block copolymer may be selected from the group consisting of PS-b-PMMA (polystyrene-block-polymethylmethacrylate), PS-b-PEO (polystyrene-block-polyethyleneoxide), PS- B-PDMS (polystyrene-block-polydimethylsiloxane), PS-b-PFS (polystyrene-block-polyferrocenyldimethylsilane) or PS-b-PI (polystyrene-block-polyisoprene). 5. The method of claim 4,
Further comprising the step of ultraviolet treatment or heat treatment of the first thin film. The method of claim 1,
And forming an intermediate layer between the substrate and the first thin film. The method of claim 1,
Wherein the cylindrical first block copolymer forms a hexagonal type unit body. Forming a first thin film including a first block copolymer on a substrate on which a parent pattern layer is formed,
Forming a guide pattern on the first thin film,
Forming a second thin film including a second block copolymer between the guide patterns,
Curing the second thin film to form a sacrificial structure including a first sacrificial block and a second sacrificial block,
Removing the first sacrificial block from the sacrificial structure, and
Patterning the first thin film and the parent pattern layer using the second sacrificial block as a mask,
Wherein the first block copolymer is a cylinder type and the second block copolymer is a lamella. 11. The method of claim 10,
Wherein the guide pattern is formed of a photoresist. 12. The method of claim 11,
Wherein the guide pattern includes a photoresist pattern portion extended along a first direction and the photoresist pattern portion is repeatedly arranged in a second direction different from the first direction. The method of claim 12,
Wherein the first block copolymer comprises a crosslinking material. The method of claim 13,
Wherein the crosslinking material comprises one of ketene, azide or benzocyclobutene (BCB). The method of claim 13,
The second block copolymer may be selected from the group consisting of PS-b-PMMA (polystyrene-block-polymethylmethacrylate), PS-b-PEO (polystyrene-block-polyethyleneoxide), PS- PS-b-PDMS (polystyrene-block-polydimethylsiloxane), PS-b-PFS (polystyrene-block-polyferrocenyldimethylsilane) or PS-b-PI (polystyrene-block-polyisoprene). The method of claim 13,
Further comprising the step of subjecting the first thin film to UV treatment or heat treatment. 11. The method of claim 10,
And forming an intermediate layer between the parent pattern layer and the first thin film. 11. The method of claim 10,
Wherein the parent pattern layer is patterned in a line lattice pattern. The method of claim 18,
Wherein the parent pattern layer comprises a reflective metal. 11. The method of claim 10,
Wherein the cylindrical first block copolymer forms a hexagonal type unit body.

Images